2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95173In 1958 Lax conjectured that hyperbolic polynomials in three variables are determinants of linear combinations of three symmetric matrices. This conjecture is equivalent to a recent observation of Helton and Vinnikov.7 pages, Proceedings to the AMS, to appear. Added background materialOptimization and Control15A45; 90C25; 52A41text